Paraffin wax compositions having improved flexibility



Dec. 1, 1959 V v K. G. ARABIAN PARAFFIN WAX COMPOSITIONS HAVING IMPROVED FLEXIBILITY Filed Feb. 28, 1955 CUMULATIVE "/0 MOL n-PARAFFINS llillll ll llILIII I6 I8 20 22 24 26 28 3O 32 34 NUMBER OF CARBON ATOMS n- PARAFFIN DISTRIBUTION IN I00 DISTILLATE WAX FROM MASS SPEGTROMETER ANALYSIS TEMPERATURE,

FIG. I

TIME IN MINUTES HEATING CURVES FIG. 11

INVENTOR KAREKIN G. ARABIAN 3 Sheets-Sheet 1 may m HIS AGENT Dec. 1, 195

9 I K. e. ARABIAN 2,915,447

PARAFFIN WAX COMPOSITIONS HAVING IMPROVED FLEXIBILITY Filed 'Feb. 28, 1955 TEMPERATURi TEMPERATURE 3 Sheets-Sheet 2 MELTED WAX e-FoRM l C20 C23 PHASE DIAGRAM LIQUID STABLE or- FORM STABLE B- FORM PHASE DIAGRAM FIG. I!

INVENTO'RI I KAREKIN e. ARABIAN HIS AGENT Dec. 1, 1959 K. s. ARABIAN 2,915,447

. PARAFFIN WAX COMPOSITIONS HAVING IMPROVED FLEXIBILITY Filed Feb. 28, 1955 I I 3 Sheets-Sheet 3 I I I l l I l I I I l l I I I |3 [:1 n-PARAFFINS (90.6%MOL) .J Z lSO-PARAFFINS (8.2%MOLI" 2 I6 I NAPHTHENES ILZ'AMOLI l4 '5 I- e 5 o 6 g o 4 2 a Q M lll /l "11/31/111 IIIII:

IT 8 I9 20 2| 22 23 24 25 2e 21 2a 29 30 3| 32 3a NUMBER OF CARBON ATOMS COMPOSITION oFlzsF MP PARAFFIN WAX FIG. 1

NO. OF DEGREES BEND AT 25C 0| CI6H34 I 2o 42 24 o a aa 22 46 CARBON NO. OF n-PARAFFIN ADDED THE EFFECT OF 8% n-PARAFFIN OF VARIOUS MOL. WTS.

ADDED INDIVIDUALLY TO I38-l40 FULL RANGE PARAFFIN WAX (MEASURED BY BEND TEST l/2' THICK SPECIMEN) FIG. 21

INVENTOR= KAREKIN G ARABIAN PARAFFIN WAX COMPOSITIONS HAVING IMPROVED FLEXIBILITY Karekin G. Arabian, Houston, vTern, assignor to Shell Development Company, New York, N.Y., a corporation of Delaware Application February 28, 1955, Serial No. 490,980

4 Claims. .(Cl. 20821) This invention relates to improved paraffin wax compositions. More particularly, it is concerned with wax compositions having improved flexibility.

Parafiin waxes, obtained usually from petroleum disstillates, but in special instances from petroleum residues, comprise predominantly normal paraflin hydrocarbons with minor proportions of isoparafiins and naphthenes. The range of hydrocarbons present in parafiin waxes obtained from a given petroleum distillate is continuous with no gaps from the lowest to the highest members. Thus, the paralfin wax obtained by dewaxing a typical lubricating oil distillate from an East Texas crude; to produce a refined lubricating oil having a viscosity of 100 SUS at 100 F., contains normal paraffins having from 13 to 31 carbon atoms and, according to either fractional crystallization or spectrographic data, none of the intervening individual members is absent. Since the normal paraflins in ordinary paraflin wax obtained from the usual petroleum oil distillates comprise about 70-90% of the waxes, it will be understood thatfthe physical properties of these normal paraffins, both-individually and collectively, determine the averagefprope'rties of the commercial wax product toa substantial extent. f "f Certain properties are desirable in'paraffin *waxes which make them useful for specific purposes including temperature at which flexibility is most desired. The foregoing objects will be more fully understood and other objects will become apparent from the description of the invention, which will be made with reference to the accompanying drawing, wherein:

In the accompanying drawings, Figs. I and V repre sent the normal parai'fin distribution in typical full-range parafin waxes; Fig. II shows the heating curves for two normal hydrocarbons and mixtures thereof; Figs. III and IV are phase diagrams of certain wax combinations; and Fig. VI shows the effect on flexibility of proceeding according to the invention to be described.

Now in accordance with the present invention, it has been found that the flexibility of paraiiin wax compositions at a temperature, T can be greatly improved by combining with a full-range paraffin wax between 5% and about 30% by weight, based on the combined product, of a straight chain (normal) paraffin wax A having between about 17 and 36 carbon atoms per molecule, such that a fraction B of the combined product comprising at least about 5% by weight thereof, has a melting point above T, and a transition temperature below T, and at least 50% of fraction B is wax introduced in wax A, and the combined product has an average melting point higher than T.

More particularly, the invention provides a method for the production of highly flexible parafiin waxes by the addition to a full-range paraffin wax, and especially those having less than 180? bend (as measured by the test described hereinafter) at temperature T, of between 5 and 30% by weight, basedon the combined product, of a wax which eitheralone or in mixed crystal form with adjacent components of the full range paraffinwax will form a plasticizing fraction having maximum plasticity at about the temperature at which maximum flexibility is desired, so that at temperature T the composiductility, tensile strength, flexibility, softening point,

melting point, and transition point. The properties of a wax suitable for a particular purpose such as bread wraps, and the like, are not necessarily those desirable for other uses wherein low temperatures are encountered, as in freezer wrappers or milk cartons.

Numerous additive materials and producing techniques have been utilized in attempts to improve one or more of the physical properties of various waxes. These have included the additionof microcrystalline, i.e. amorphous tion has a bend (measured as described hereinafter) at least about 5 greater than that of the unmodified fullrange wax.

In the discussion which follows, the following terms will be understood to have clearly defined meanings:

" parafiin waxes are understood to be those which in their L if any, of non-normal hydrocarbons.

or residual, waxes to the paraflin waxes for certain purposes, but it has been found that the addition of microcrystalline wax to'a parafiin wax merely results in a composition having intermediate properties between these two basic components. With respect to processing techniques, various recycling operations have beencarried out so as to incorporate some of the softer waxes into the paraffin wax compositions, but the result'is essentially the same as adding microcrystalline wax thereto. A further processing technique has been to fractionate a distillate wax into narrow cuts and re-blend nonadjacent cuts for the purpose of increasing the tensile strength of the compositions. This, of course, requires extensive plant processing and furthermore does not utilize the full range of waxes'produced from a paratfin wax distillate.

It is an object of the present invention to improve parafiin wax compositions. It is a further object of thisinvention to improve the flexibility of paraffin waxes. It is a third object of this invention to. modify paraffin waxes so as to produce their maximum flexibility at any given most stable crystalline form are highly crystalline and normally brittle materials, predominating in normal paraflin hydrocarbons, and containing only small amounts,

They are distinguished in this respect and other properties from the socalled amorphous or microcrystalline waxes, which are of much more complex structure and are normally to be found in the soft waxes or residual wax fractions. The term full-range parafiin waxes will be understood to mean a paraffin Wax as obtained by a normal dewaxing procedure (usually followed by deoiling of the wax product separated by the dewaxing) from a lubricating oil distillate and containing normal paraffin hydrocarbons 5 (and minor proportions of non-normal hydrocarbons) over a given range, say, from 18 to 39 carbon atoms, or

for any shorter range within this broad spectrum without any of the intervening normal paraiiins having been removed, such as shown in Figure I. The melting point of the wax is understood to be the average melting point as determined by a standard ASTM procedure. The transition temperature of a parafiin wax is that temperature at which the crystalline wax changes from the relatively plastic alpha form to the beta form. This property will be discussed more fully hereinafter.

Since it is from its solid state properties that a wax derives its commercial value, a higher wax melting point favors a wider range of practical applications; consequently, the wax melting point has been generally supposed to be an important factor in quality evaluation.

However, it has been determined that this conclusion is not altogether correct, especially in view of the fact that normal paraflins have been found to exist in at least two solid crystalline states. The crystalline states which are most important are the so-called alpha form, which is just below the melting point of the wax, and the beta form, which the wax crystal assumes at a temperature below that of the alpha form. The beta form of normal parah'ins is the more stable of the two and the individual normal paraffin hydrocarbons when in the beta form are extremely brittle and exhibit substantially no ductility whatsoever. Individually, therefore, a single normal parafiin hydrocarbon wax is extremely weak. In the alpha form a small stress causes slipping of the soft crystalsover each other, resulting in a certain elongation of the specimen before a break occurs. Below the transition temperature the extreme rigidity of the individual crystals results in a very brittle structure. The breaking strength below'said transition temperature is equally low for all normal paraffins, in the order of 14 kilograms per square centimeter.

Mixed crystals change this property in that the depression of transition point below the melting point of the mixed crystal is substantially greater than that which exists for any of the individual members forming a part of the mixed crystal. In accordance with one aspect of the present invention, it has been found that mixed crystals are formed between normal parafiins having no more than about 4 carbon atoms difference between the molecules and that, within this range, the greatest depression in transition temperature occurs between the pairs of normal hydrocarbons having the greatest carbon atom difference (4) per molecule.

In the alpha form, the hydrocarbons are in the hexagonal system of crystallinity, thus forming crystals wherein the hydrocarbon molecules are attached side by side like hexagonal pencils, the long axes being perpendicular to the plane formed by the ends of the molecules. The molecules rotate freely about their long axes. In the beta form the crystals are in the orthorhombic system wherein the packing is no longer symmetrically hexagonal. Two unequal side spacings are shown and the molecules do not possess the freedom of rotation, but show vibration about their mean positions.

The point of transition is clearly manifested by the sharp discontinuity in the curve of hardness. In the alpha modification the crystal is much softer, owing to the rotation of the long chains about their axes, than in the beta modification. This rotation keeps the chains at a greater distance from each other. In the alpha form the coefiicient of expansion is many times greater than in the beta form, and consquently, a sharp decrease in hardness occurs on slightly increasing the tcmperatrre. Because of this, normal paraflin hydrocarbons in their alpha form are semi-fluid plastic members, as opposed to the hard brittle crystalline state of the beta form.

The transition point of a wax may be readily determined experimentally by means of a heating or cooling curve of temperature versus time for a constant heat input. When heating an ordinary single normal paraifin (which is in the beta state) the temperature-time curve rises diagonally until the transtion point has been reached, at which time the curve bends to a substantially horizontal direction until all of the wax being tested has been converted from the beta to the alpha form. At this point the heating curve assumes a diagonal direction until the melting point is reached, at which time the heating curve again bends to the horizontal until all of the specimen has been melted. Thereafter, since the specimen is in the liquid state entirely, the heating curve again assumes the diagonal direction.

The horizontal portions of the curve denoting the transition temperature between alpha and beta forms and the melting point temperature are clearly defined. This will be seen in Fig. II which shows heating curves for 4 normal C parafi'in hydrocarbon, normal C parafiin hydrocarbon, as well as for three intermediate mixtures of these two individual members.

The significance of the mixture of hydrocarbons upon the melting point and the transition point will be seen by reference to Fig. III. In this figure, the upper curves represent the melting points of various mixtures determined by both heating and cooling. The lower curves ing Fig. III represent the transition points of various mixtures of C and C normal hydrocarbons. Note that a maximum depression of the transition temperature occurs when C is mixed with C in a ratio of approximately 9:1 and that mixtures between about 9:1 and about 1:1 exhibit a wide temperature region of alphaform. Note furthermore that a difference between the transition temperature and melting point for the mixtures is substantially greater than for either of the individual wax members alone. Thus, it will be evident that a means may be found for depressing the transition temperature and thus permitting a wider area to exist wherein the plastic alpha form of the crystals is present.

It has been found, however, that the proportion of any one individual wax member present in a full-range distillate wax is seldom (if ever) sufficient to provide the desired large degree of depression in the transition temperature. The present invention is designed to overcome this shortcoming of commercially produced full-range paraffin waxes. Table I presents pertinent physical data for individual normal alkanes:

TABLE I Transition Normal Alkane M. P., C. Tem geature,

C 1 Cm Cm Several things are noteworthy from the properties given in the Table I. First, a substantial difference exists between melting point and transition temperature of the individual normal alkanes having an odd number of carbon atoms per molecule. Contrasted to this, it will be seen that the individual normal alkanes having an even number of atoms per molecule exhibit substantially no difference between the melting point and the transition temperature.

In its preferred form the present invention comprises the addition of one or more waxes to a full-range paratfin wax such that the combined composition contains a sufficient number of parafiin wax crystals having a transition temperature below, but a melting point above, the temperature at which maximum flexibility of the combined composition is desired. It will be understood that this can be effected in two principal ways. First, the combined composition may comprise a full-range paraffin wax to which has been added a normal paraffin hydrocarbon (or narrow range mixture thereof) which is discontinuous with the series of normal paraffins present in the full-range paraffin wax. This would occur, for example, by the combination of normal nonadecane with the full-range paraflin wax obtained from a medium boiling distillate which contains normal paratfins having from about 23 to about 36 carbon atoms per molecule. Under these circumstances, and when the normal nonadecane is present in an amount between about 5% and about 30% by weight of the combined fractions, the

32. C. This is due to the fact that the proportion of normal nonadecane added to the full-range paraflin' wax is .suflicient to plasticize the entire wax combination when the nonadecane is in the alpha form... According to Table I, it will be seen that the alpha form exists be-' tween 23 (the transition temperature) and 32.1 C. (the melting point).

The situation is complicated substantially if the added paraflin wax is less than about 3 carbon atoms difference in length from the closest individual members present in the full-range paraffin wax. Under these conditions, mixed crystals may form between the added wax and the more nearly adjacent members of thefulbrange wax. The depression in transition temperature of these mixed crystals is such as to sprcad out the area'wherein the alpha form existsand thus to enable a greater plasticizing action of the combined waxes to occur. This will be evident by reference again to Fig. III.

The ability to co-crystallize with adjacent members in the normal hydrocarbon series means that even the evennumbered normal alkanes may be utilized in accordance with the present invention, since the co-crystallization of even-numbered normal paraflins with adjacent normal paraflins causes a difference to be created between the transition temperature and the melting point where no difference occurs in the pure even-numbered alkanes. This can be seen by reference to Fig. IV which represents the phase diagram of mixtures of C and C normal alkanes. As will be seen by reference to the melting points and transition points in Table I, there is no difference between these two properties of normal C alkane. There is a relatively small difference between the two properties of the corresponding normal C alkane. However, when these two are mixed in varying proportions as Fig. IV shows, there is a substantial depression in the transition temperature and the maximum depression occurs wherein approximately nine parts of C are mixed with about one part of C This illustrates the aspect of this invention that if the normal hydrocarbon added to the full-range hydrocarbonis present in a sufficient amount, i.e. -30% by weight of the combined wax, and the full-range wax contains a suflicient proportion of hydrocarbons-less than about three carbon atoms different in length from normal cgorthen a relatively wide temperature range wherein the alpha form (the plastic state) is present in a plasticizing amount will exist and the wax composition will have an improved flexibility. The precise temperature at which this improved flexibility will occur will depend upon two principal factors, namely, the proportion of C added, and the identity and proportion of the nearly adjacent hydrocarbons present in the full-range paraffin wax.

The data contained in Table I indicate that a second member may be added, in an amount of at least 5% by weight of the combined waxes, to a full-range paraffin wax, so as to obtain high flexibility at a desired temperature. It is true, as will be seen from the full-range paraffin wax composition curves in Figs. I and V and described hereinafter, that the full-range wax contains certain adjacent wax members in an amount sufficient to provide a limited degree of flexibility at a given temperature. But the present invention provides far greater flexibility and effect by the calculated addition of the precise normal paraffin to a given full-range paraffin wax so as to produce, or enhance, flexibility at any specifically desired temperature.

For example, and by way of illustration, it may be assumed, first, that flexibility is desired for a particular use at a temperature of 42 C., and secondly, that a fullrange paraffin wax having an average melting point in the order of 50 C. is to be modified for this purpose. Reference to Table I will show that the optimum normal paraffin to be added in an amount of between 5 and byweight of the final "composition, in' 'acc'ordance' with this invention, should be the normal C alkane, having a" transition temperature of 40 C. and a melting point.of 47.5 C. Hence, since flexibility is desired at a tempera? ture of 42 C., this added wax provides the plasticizing effect essential for a high degree of flexibility in the full-range wax. This effect will be provided even if the full-range wax contains only normal paraffin waxes which are relatively non-adjacent to the C normal alkane,or if the C added wax is adjacent to individual members of the full-range wax. The greatest effect, of course, will be found by utilizing the present invention'to enhance the flexibility of a full-range wax at a specified tempera: ture which is outside the alpha-form range of any of the major components of the full-range wax.

This will be understood more fully by reference to Fig. V, which shows the distribution of hydrocarbons throughout a typical full-range parafiin wax obtained from a medium-low viscosity lubricating oil distillate. It will be seen by reference to this figure that the proportions of isoparaflins and of naphthenes are negligible; also, that the proportions of normal alkanes having from 17 to 21 carbon atoms and from 28 to 31 carbon atoms are lessthan 4% for each of the individual members. Now, if high flexibility is desired at a temperature of 25 C., this full-range paraffin wax will fail to pass a flexibility test. This is due to the fact that at 25 C. (see Table I), the wax contains entirely too small percentages of the waxes which will be in the alpha form at the temperature at which maximum flexibility is desired. This illus: trates the advantage which would be gained by preferred use of the present invention, wherein a full-range paraffin wax is modified by 5 to 30% by weight of the wax composition of an additive wax which will enhance the proportion of at least one of the waxes present in the fullrange wax present therein originally in a proportion less than about 5% For example, if the full-range wax shown in Fig. V is modified with about 5% of normal C1 hydrocarbon, the flexibility at the specified temperature of 25 C. will be greatly enhanced, since at this temperature the added C is in the alpha form, as will be found by reference to the transition-melting point table (Table I).

The data in Table II show the weightand moi-percent of the individual normal paraffins present in two typical distillate full-range paraffin waxes.

TABLE II Distribution of n-parajjins in commercial waxes as analyzed by mass spectrometer [Basis 100% n-Paraffins] 123 F., M.P., Wax 138.8 F., M.P., Wax

n-Paraflin Percent w. M01 Per- Percent w. Mol Percent cent; cent In illustrating a specific application of the present invention, and to indicate the expected and highly effective results obtained by application of the invention to a specific wax mixture, the second of the two waxes described in Table II was modified by the addition thereto of 8% by weight of the final mixture of individual normal paraffins having from 16 to 22 carbon atoms per molecule. Fig. VI shows the results obtained by testing these modified Waxes at a test temperature of 25 C. The bend test is performed by casting a specimen one-half inch thick in a Perkins tensile strength mold, allowing the specimen to stand for three hours in a constant temperature room at 25 C. and then bending manually. The degrees through which the specimen may be bent prior to breaking is recorded. In order to pass this test, the specimen must bend at least 4 degrees. As Fig. VI shows, the addition of either a C C C or C normal alkane to this particular full-range paraffin wax resulted in no beneficial effect upon the flexibility of the combined wax composition. However, the addition of C n-alkane resulted in an outstanding increase in the flexibility of the full-range wax, and the addition of a C or a C n-alkane enabled the modified composition to pass the bend test, although the increase in flexibility was of a minor order.

The explanation of these phenomena will be understood more fully by a view of the theoretical background for the present invention, given hereinbefore and spe- 'cifically by reference to the transition point-melting point table, also given hereinbefore. Since the alpha form of C is that which exists at the test temperature of 25 C., and since the alpha form of the other additive waxes occurs at temperatures other than the test temperature, the reason for the outstanding results using C in this particular case will now be understood. The beneficial but minor effects of C and C can be accounted for by mixed crystal formation occurring between the added Waxes and the minor amounts of individual adjacent or near adjacent members present in the full-range wax being modified. It will be understood that if the test temperature had been, for example, at 42 C. instead of 25 C., then the most effective additive Wax would have been C n-alkane.

It is essential for the success of the present invention that the additive wax have a melting point above the temperature at which enhanced flexibility is desired. If the melting point of the additive wax is below this test temperature, then the resulting combined wax composition will have undesirable properties. It may, for example, be crumbly and similar to an undeoiled wax since the additive wax, if it is present above its melting point, will in fact be an oily liquid.

It will be noted that the wax modified in the tests presented graphically in Fig. VI had a melting point of about 138.8 F. The invention, of course, is not restricted to the use of this particular full-range wax and moreover, the effect of the addition of normal C is not confined to the improvement of this particular wax. The effect of normal C as an additive wax is, on the contrary, dependent upon the correlation between the temperature at which enhanced flexibility is desired and the temperature range in which normal C is in the alpha form. This is demonstrated by the modification of a full-range paraflin wax having a melting point of about 126 F. with 2.0% by weight, of the final composition, of normal C While the unmodified full-range paraflin wax is brittle at the test temperature of 25 C., the combined composition can be bent more than 180 degrees without breaking. This is true also when 20% of the normal C is added to the 138.8" F. melting point full-range paraffin wax. Comparison of these data with the results obtained by the addition of the same normal alkane in an amount of 8% (see Fig. VI) will indicate the advantages gained by adding proportionately higher amounts of the additive material.

It will be understood, of course, that it is unnecessary to'add pure individual hydrocarbons as the additive flexibilityimproving wax. It is preferred, however, that the additive wax be one having a relatively narrow range of individual wax members and that more than 50% of the additive wax should have a normal paraffin spread of not more than about four carbon atoms. For example, the addition of 10% of a gas oil wax, from a'straight run gas oil distillate from East Texas crude, to the same 126 F. melting point full-range parafiin Wax provided 'a Bend test of 5 degrees. The gas oil wax had the following composition:

Composition of wax from gas oil Percent non-normal paratfins 9.6%.

Due to the fact that the normal alkanes having an even number of carbon atoms per molecule have a transition point which is substantially identical with the melting point of the wax, the individual even-numbered alkanes are highly brittle materials at any temperature. However, as pointed out hereinbefore, this does not prevent their use in full-range paraflin waxes, especially where the full-range wax contains minor amounts of normal alkanes which are less than about three atoms removed from the carbon length of the additive wax. This is illustrated by the modification of the full-range paraffin wax having a melting point of 138.8 F. with 5% by weight of normal C alkane. In spite of the fact that both the additive wax and the full-range wax were brittle at the test temperature of 25 C. (snapping after less than one degree bend), the combined composition could be bent at least 45 degrees before breaking. This is, of course, due to the depression of the transition point by the formation of mixed crystals.

While the present invention can be applied particularly to full-range paraflin waxes having a carbon atom spread of 18 to 39 carbon atoms per molecule, it can be applied to other paratfin wax mixtures having an even wider or norrower carbon atom range. For example, the fullrange wax having a melting point of about 123 F. has a continuous range of normal paraflins from about C to about C Also the full-range parafiin wax having a melting point of about 138.8 F. has a carbon atom range from about C to about C The most effective additive waxes for the production of maximum flexibility at temperatures commercially usable today are the normal alkanes having between about 19 and 22 carbon atoms per molecule. The present invention especially provides a means for imparting flexibility to a full-range wax at a temperature whereat the latter is not completely in the alpha form.

I claim as my invention:

1. A wax composition comprising 70-95% by weight of a continuous series of normal paraffin hydrocarbons having from about 18 to about 31 carbon atoms per molecule, the individual C hydrocarbons being present in an amount less than about 5% by weight each and 53()% of normal nonadecane, said composition having a greater flexibility at a temperature between 23.0 C. and 32.1 C. than that of the continuous series of hydrocarbons in the absence of the added nonadecane. 1

2. A wax composition comprising 70-95% by weight of a continuous series of normal paraflin hydrocarbons having from about 18 to about 31 carbon atoms per molecule, the individual C hydrocarbons being present in an amount less than about 5% by weight each and 5-30% of normal eicosane, said composition having a greater 9 flexibility at a temperature between 23.0 C. and 32.1 C. than that of the continuous series of hydrocarbons in the absence of the added eicosane.

3. A wax composition comprising 70-95% by weight of a continuous series of normal parafiin hydrocarbons having from about 18 to about 31 carbon atoms per molecule, the individual C hydrocarbons being present in an amount less than about 5% by weight each and 5-30% of normal C parafiin hydrocarbon, said composition having a greater flexibility at a temperature between 23.0 C. and 32.1 C. than that of the continuous series of hydrocarbons in the absence of the added C parafiin hydrocarbon.

4. A wax composition comprising 70-95% by weight of a continuous series of normal paraffin hydrocarbons having from about 18 to about 31 carbon atoms per molecule, the individual C hydrocarbons being pres ent in an amount less than about 5% by weight each and 530% of normal C paraffin hydrocarbons, said composition having a greater flexibility at a temperature be- 10 tween 23.0 C. and 32.1" C. than that of the continuous series of hydrocarbons in the absence of the added C1941 parafiin hydrocarbons.

References Cited in the file of this patent UNITED STATES PATENTS 

4. A WAX COMPOSITION COMPRISING. 70-95% BY WEIGHT OF A CONTINOUS SERIES OF NORMAL PARAFIN HYDROCARBONS HAVING FROM ABOUT 18 TO ABOUT 31 CARBON ATOMS PER MOLECULE, THE INDIVIDUAL C18-21 HYDROCARBONS BEING PRESENT IN AN AMOUNT LESS THAN ABOUT 5% BY WEIGHT EACH AND 5-30% OF NORMAL C19-21 PARAFFIN HYDROCARBONS, SAID COMPOSITION HAVING A GREATER FLEXIBILITY AT A TEMPERATURE BESERIES OF HYDROCARBONS IN THE ABSENCE OF THE ADDED C19-21 TWEEN 230*C. AND 32.1*C. THAN THAT OF THE CONTINOUS PARAFFIN HYDROCARBONS. 